Process of dyeing with vat dyes



Patented Jan. 19, 1937 PATENT OFFICE raocnss or DYEING wrrn VAT mms Jean G. Kern, Hamburg, N. Y., assignor to National Aniline & Chemical Company, Inc., New

York, N. Y., a corporation of New York No Drawing. Application April 8, 1935, Serial No. 15,262. In Japan September 3, 1934 9 Claims.

This invention relates to the art of dyeing with vat dyes. It relates especially to a new class of assistants for the dyeing of textile fibers, and especially those of the vegetable type, such as cotton, regenerated cellulose and the like, with vat dyes by means of a dye bath or dye liquor containing a vat dye in the reduced form, whereby dyeings of excellent fastness, penetration, depth and brilliance may be obtained.

As is well known, vat dyes are solid substances which are insoluble in water. In the dyeing of textile fibers with vat dyes, the insoluble vat dyes are converted to a reduced form, in which form they are taken up by the fiber, and then the fiber is subjected to an oxidizing or fixing treatment whereby the dyestufi is again rendered insoluble. In general, the dyeing process involves treatment of the fiber to be dyed with the dye bath or dye liquor, containing the reduced compound (leuco-compound) of the vat dye. A number of procedures are employed in carrying out the process, as for example, working piece goods (cotton, regenerated cellulose, etc.) and raw cotton stock (unspun cotton fiber) in the dye bath (vat), pad dyeing piece goods by passing rapidly through the dye bath, treating raw cotton stock in a dyeing machine with the dye liquor, working yarn on beamsin the dye bath, treating yarn in package dyeing machines with the dye liquor, etc.

The preparation of the dye bath or dye liquor generally involves diluting with water a vat dye paste or powder (containing the vat dye in the ordinary, unreduced form, usually after screening to insure desired fineness of the vat dye particles) and mixing it with alkali (e. g. sodium'hydroxide) and a reducing agent (e. g. sodium hydrosulfite) in suitable amounts to form a bath of the reduced (leuco) compound of the vat dye, while heating to the temperature suitable for the particular vat dye used. The resulting bath or liquor is then employed in the dyeing operation.

, For economical dyeing it is desirable that maxi mum utilization of the vat dye be secured, thatthe dyeings be thoroughly penetrated, and that the color be uniform (level) and bright.

The present invention is based upon the discovery that the soluble salts of the acid reaction products resulting from the interaction of an aliphatic alcohol containing less than 6 carton atoms with a polybasic inorganic acid or suitable derivative thereof possess a combination of properties which render them of particular value for use as assistants in the dyeing of textile fibers, and especially those of the vegetable type, such as cotton, rayon (regenerated cellulose) and the like, by a process in which the fiber to be dyed is treated with a non-acid dye bath or dye liquor containing a vat dye in the reduced (leuco) form and preferably also containing an alkali. Thus, the soluble salts of the acid reaction products of sulfuric acid or chlorsulfonic acid upon the allphatic monohydric alcohols which contain or less carbon atoms, which products are considered to be acid alkyl sulfates corresponding with the formula ROSO3H (in which R is a hydrocarbon radical containing not more than 5 carbon atoms), as well as others of the hereinafter described soluble salts of acid alkyl esters of inorganic polybasic acids, have no tendency to cause the resulting dye baths and dye liquors tofoam or lather by reason of the presence of the said salts. They have the further advantageous property of acting as assistants in the absorption or adsorption of the reduced compounds of the vat dyes by the fiber, and in the penetration of woven fabric by the reduced compounds of the vat dyes. The alkyl ester salts of the present invention apparently act on both the vat dye and the fiber itself, causing more effective absorption of the leuco compound of the dye.

The acid alkyl esters, the soluble salt of which may be employed in accordance with the present invention, include the partial esters of polybasic inorganic acids (as for example, of sulfuric, phosphoric, boro-sulfuric, boro-phosphoric, boric, silicic, eta, acids) and especially those of sulfuric and phosphoric acids, containing at least one aliphatic hydrocarbon radical (straight-chain, branched-chain, saturated or unsaturated) which contains not more than 5 carbon atoms, as the organic (ester) radical or radicals. These partial esters (which are herein designated as acid 1 alkyl esters") may be represented by the formula in which it represents an aliphatic hydrocarbon radical which contains not more than 5 carbon atoms,

A represents the residue of the inorganic acid (as for example, the radical S02. the radical PO,

soluble salts of the herein described acid alkylesters, e. g., those resulting from the combination of any suitable metal or base, including the"organic bases, with the-said acid alkyl esters. It

is particularly advantageous, however, to use the alkali metal salts of the acid alkyl sulfates, phosphates, boro-sulfates and boro-phosphates or the salts formed by the interaction of the saidalkyl sulfates, phosphates, borossulfates and borophosphates with aliphatic or aromatic amines, for example, the alkylol amines. Thus the potassium and sodium salts of the said acid alkyl esters, or the salts of the acid alkyl esters with diethanolamine, triethanolamine, pyridine, or other saltforming ammonium bases, may be used. The sodium salts, in view'of their extremely high solubility in water and alkaline dye baths and dye liquors are of especial value.

The said salts of alkyl esters employed in accordance with the present inventionmay be prepared in any manner well known to the art; as

for example, by the treatmentof the corresponding alcohol, in the presence or absence of a solvent or diluent, with a suitable inorganic reagent (such as phosphoric acid, phosphorus chloride or oxychloride, concentrated sulfuric acid, and/or chlorsulfonic acid, and/or one or more of these in the presence of boric acid, etc.) and neutralization of the resulting acid alkyl ester with an inorganic or organic base which forms a readily soluble salt with said acid alkyl ester. It may be noted that the alkyl sulfuric acids and the alkyl hero-sulfuric acids resulting from the use of sulfuricacid or chlorsulfonic acid, in the absence or presence of boric acid, may contain varying amounts of sul-,-

- fonic acids which are sometimes produced due to secondary reactions; the presence of such sulfonic acids, however, does not impair the usefulness of the alkyl sulfuric acids, and alkyl borosulfuric acids in accordance withthe present invention.

As illustrating acid alkyl esters, the soluble salts of which may be employed in accordance with the present invention, the following -may be mentioned: the mono-ethyl, propyl, butyl and amyl sulfuric acids; the ethyl, propyl, butyl and amyl boro-sulfuric acids; the monoand di-ethyl,

'propyl, butyl and amyl phosphoric acids; the

ethyl, propyl, butyl and amyl hero-phosphoric acids, etc.

Of special interest in connection with the present invention are the various soluble salts, and' 2,067,929 atoms of the parent polybasi'c inorganic acid has carbinolt pentene-2-sulfuric acid; normal amyl sulfuric acid; tertiary amyl sulfuric acid; amylene sulfuric acid; etc. The salts of the monoalkyl sulfuric acids which contain from 3 to 5 carbon in which the alkyl group is a normal or straightchain radical.

The said sulfuric acid mono esters may be prepared, for example, by the treatment of the corresponding alcohol, in the presence or absence of a solvent or diluent, with a suitable 'sulfonating agent (such as concentrated sulfuric acid and/or chlorsulfonic acid or the like), or by the inter-.- action of sulfuric acid or the like with the corresponding unsaturated hydrocarbon. Thus, 'a

suitable alcohol dissolved in an inert organic solvent may be reacted with the necessary amount of 'sulfonic acid to form the sulfuric acid mono ester of the alcohol, the mixture then may be blown with air to remove hydrogen chloride formed, and subsequently stirred with water.

Mixtures of salts of the saidacid alkyl esters may also be employed in accordance with the present invention. For example the saltsof suitable inorganic or organic bases with the commercially available and cheap mixtures of alkyl sulfuric acid resulting from the sulfuric acidv treatment of mixed gaseous and lighter liquid unsaturated hydrocarbons, such as the mixtures produced in the recovery and removal of unsaturated hydrocarbons inthe production and purification of gasoline in the so-called cracking process of petroleum distillation.

The percentage of assistant of the present invention that may be employed is not critical and improved results are obtained with even as little as 1 per cent or 2 per cent (based on the total weight of the dye bath or dye liquor).

The advantageous action of the said salts of the acid alkyl esters may be secured in a number of ways. Thus the said alkyl ester sailts may be incorporatedjinto the usual dye baths and dye liquors or into the dyestuif pastes employed in preparing the. dye baths and dye liquors. The said alkyl ester salts are in general crystalline products and hence may be added directly to the'usual dye baths or dye liquors to cause the desired effect. Further, an advantageous action may be secured by subjecting the cloth to be dyed to a preliminary treatment with the solution of the said alkyl ester salt, as for example, impregnation. In copending application Serial No. 673,030, filed May 26, 1933, vat dye compositions in the form of powders are described containing vat dyestufls and alkyl ester salts of the type herein disclosed. Such compositions, in view of their content of said alkyl ester salts, may be employed in accordance with the present invention merely by substituting them 2,067,929 .for the vat dye pastes usually employed and dyeing in the ordinary manner.

The acid alkyl esters may also be employed as such in dye liquors containing alkali inasmuch as the salts of said acid alkyl esters will be formed in the resulting compositions and there exert their advantageous action.

If desired, foam-breaking or foam-preventing agents may also be included inthe compositions of the present invention in connection with vat dyes which have a tendency to produce foaming.

The invention may be employed in connection with vat dyes of all types including those derived from anthraquinone, indophenols, various indigoid, thioindigoid and indirubin compounds, etc.; as for example, indanthrones, pyranthrones, flavanthrones, dibenzanthrones, isodibenzanthrones, perylene quinones, anthanthrones, di-' benzpyrene quinones, anthrimidocarbazols, naphthacridones, indigo, thioindigo, indirubin, etc., including derivatives thereof, such as their halogen, nitro, sulfur, and/or alkoxy derivatives.

Examples of vat dyestuffs with which the present invention may beemployed are such indigoid and thioindigoid dyestuffs as the following:

National vat orange R Color Index No. 1217 Color Index No. 1212' National vat red violet RH 5,5'-dicl1lor-7,7-dibrom indigo National brilliant indigo 4G National brilliant indigo B National brilliant indigo 4B.

National vat violet R National vat green G National vat pink (6,6' dichlor-4,4' dimethyl-2, 2-bis-thio-naphthenindig National vat pink BG National vat yellow G National vat yellow B And such anthraquinone vat dyes as the lol- Color Index No. 1188 Color Index No. 1189 Color Index No. 1190 Color Index N o. 1184 Color Index No. 1228 Color Index No. 1222 Color Index No. 1199 Color Index No. 1210 Color Index No. 1196 Color Index No. 1170 Color Index No. 1106 Color Index No. 1109 Color Index No. 1113 Color Index No. 1118 Color Index No. 1097 Color Index No. 1096 Color Index No. 1173 Color Index No. 1104 Color Index No. 1099 Color Index No. 1095 Color Index No. 1161 Color IndexNo. 1101 Color Index No. 1102 Color Index No. 1151 Color Index No. 1150 Color Index No. 1162 Color Index N o. 1133 National carbanthrene red BN w National carbanthrene red AFF- National carbanthrene black I Furthermore, mixtures of two or more vat dyes I may be employed, for example when: it is desired to produce compound shades such as scarlets,

navy blues, blacks and browns.

The invention is not restricted to any particular method of dyeing but includes the dyeing of piece goods and raw cotton stock (unspun cotton, fiber) in a vat, the dyeing of piece goods (cotton, rayon, etc.) by padding in a reduced bath, machine dyeing of raw cotton stock, dyeing of yarn (cotton or rayon) on beams or in package dyeing machines, etc.

The alkyl salts of the present invention are particularly valuable in the dyeing of so-called -goods (unbleached cotton fabrics, raw regenerated cellulose fabrics and the like) with vat dyes, inasmuch as the dyeings obtained with the aid of 'such alkyl ester salts have exceedingly high tinctorial value and excellent penetration as compared with dyeing made in the absence of said alkyl ester salts.

The following examples, in which the parts are by weight, will serve to illustrate the invention.

Example 1 Mercerized cotton piece goods are dyed in a vat (jigger) as follows:-

12.75 pounds of National carbanthrene blue GCD paste (containing about 17% of dye solids) are mixed with 8.16 pounds of sodium isobutyl sulfate, then 1 gallon cold water is added.

After dissolution of the sodium isobutyl sulfate is complete the mixture is passed through a fine screen. A speckless paste of excellent quality is obtained, which is then added to the following composition contained in the jigger:

Caustic soda 10 pounds Sodium hydrosulfite (conc.) 10 pounds Water gallons The temperature is raised to F. and after complete reduction of the vat dye, dyeing is started at this temperature. After one passage of the goods through the bath an additional 5 pounds of sodium hydrosulfite (conc.) is added to the bath. The temperature of the bath is raised during 30 minutes to F. The dyed cloth is washed once with water, is then passed four times through a sodium perborate bath (containing 2 pounds of sodium perborate per 100 gallons) at a temperature of 120 F., is then washed twice with cold water, passed five times through a boiling soap solution (containing 3 pounds of ordinary soap per 100 gallons), then rinsed, washed, dried and calendered.

The isobutyl sodium sulfate may be prepared, for example, by reacting 516 parts of isobutyl alcohol with 813 parts of chlorsulfonic acid at a temperature of about 14 to 16 0.; adding the resulting reaction mixture slowly to 8100 parts of Water to which 418 parts of hydrated lime, Ca(OH)z, have been added, While cooling the resulting mass to a temperature of about 20 C.; filtering ofi calcium sulfate; converting the calcium isobutyl sulfate, contained in the filtrate, to sodium isobutyl sulfate, for example, by treat ing with sodium carbonate and' removing cal cium carbonate; and recovering the sodium isobutyl sulfate in the form of a dry solid.

Example 2 100parts of boiled ofi cotton yarn is dyed in a package dyeing machine with a dye liquor containing the following ingredients:

I Parts National carbanthrene blue DR paste (containing about 16% of dye solids) or National carbanthrene violet 2R paste (containing about'1l%- of dye solids) 5 Caustic sodai 2 Sodium hydrosulfite 3 Sodium isobutyl sulfate and suflicient water to give proper circulation and dyeing conditions (e. g., about 80 to parts)- 3 tot:

The conditions of dyeing are the same as usual.

After dyeing, the yarn is rinsed, oxidized with 2% sodium perborate solution, rinsed, soaped,

rinsed and dried. The shades come out bright and very even.

It is obvious that in preparing the ,dye liquors of the above examples the ingredients may be the dye bath.

Instead of the isobutyl sodium sulfate employed in the above examples, any of the other alkyl ester salts herein described may be employed. For instance, in the above Example 2 the isobutyl sodium sulfate may advantageously be replaced by sodium isobutyl-boro-sulfate.

(The sodium isobutyl boro-sulfate may be prepared, for example, by stirring 918 parts of 100% sulfuric acid with 200 parts of boron trioxide at a temperature of 75 C. until a uniform solution results; then adding 320 parts of isobutyl alcohol in a slow stream with agitation while keeping the temperature at to C.; after stirring this solution two hours running it into a mixture of 2000 parts of caustic soda and 1000 parts of isobutyl alcohol while stirring and cooling; peremitting the resulting mixture to stratify; drawing off the aqueous layer; neutralizing that re--v maining isobutyl alcohol layer with sodium carbonate or caustic soda, heating it to boiling and filtering hot; and drying the filtrate under vacuum on a rotary drum drier.)

The presence of the salts of the acid alkyl sulfates in the dye baths and liquors produces the following advantageous results:

(1) The dye baths are more completely exhausted;

(2) Owing to the advantageous levelling and penetrating action of the said alkyl ester salts, the depth of dyeing is better equalized, giving ex.- tremely even results and excellent penetration. This is particularly true for such dyes as National carbanthrene blue GCD, National carbanthrene violet 2R, National carbanthrene blue BCL National carbanthrene dark blue DR, etc.;

(3) Due to the increased penetration there is better fixation of the dyestuff; and

(4) Due to more perfect dyeing conditions, the brllliancy of the dyeings is enhanced. Similar improved results may be obtained by substituting 12.75 pounds of the vat dye powder described in Example 10 of copending application Serial No. 673,030 filed May 26, 1933 (which contains isobutyl sodium sulfate as a part thereof) for the vat dye paste and sodium isobutyl sulfate of Example 1, and by substituting 5 parts of the vat dye powders of Examples 3 and 4 of said copending application Serial No. 673,030 for the vat dye paste and sodium isobutyl sulfate of Example 2, the amount of water being correspondingly increased.

As above indicated, the advantageous action of the salts of the acid alkyl esters as assistants in the dyeing also may be secured by pretreating the fiber with the salt of the-acid alkyl ester.

Bleached or unbleached cotton cloth is padded with a solution containing, for example, about 5 to about 30 parts per 1000 parts of water of' sodium isobutyl sulfate or any. of the other salts of acid alkyl esters herein described, for example by passing the cloth through the solution contained in a padding box equipped with squeeze rolls. Preferably, the padding liquor also contains about 2 to about 5 parts of gum tragacanth or other suitable thickener per- 1000 parts of liquor. The pressure of the squeeze rolls is preferably so regulated that the cloth retains its own weight of the padding liquor. The padded cloth is then passed through a hot air drier or over hot cans, is rolled up and is then ready for printing or dyeing. The penetration obtained this way is superior, especially for lighter shades. This process is particularly suitable for artificial fibers of the regenerated cellulose type.

It will be understood that the dyeing process as herein described may be carried out with dye baths and dye liquors containing additional assistants such as one or more of the following .hydrotropic substances, enolyzing substances,

heavy metal compounds acting as reduction ac-. celerators, catalysts or boosters, etc.

This application is a continuation-in-part of applications Serial Nos. 673,030 and 673,031, filed May 26, 1933.

I claim:

1. In the dyeing of textile fibers by forming a non-acid solution of leuco-compound of a vat dye and treating the fiber with said solution, the improvement which comprises carrying out the dyeing with the aid of a soluble salt of an acid alkyl ester containing not more than 5 carbon atoms in the alkyl group and derivable from a polybasic inorganic acid and an aliphatic alcohol containing not more than 5 carbon atoms.

2. In the dyeing of textile fibers of the vegetable type by forming an alkaline solution of a leucocompound of a vat dye and treating the fiber with said solution, the improvement which comprises carryingout the dyeing in the presence of a soluble salt of an acidalkyl ester containing not more than 5 carbon atoms in the alkyl group and derivable from a polybasic inorganic acid and an aliphatic alcohol containing not more than 5 carbon atoms.

3. In the dyeing of textile fibers of'the vegetable type by forming an alkaline solution of a leucocompound of avat dyeand treating the fiber with said solution, the improvement which comprises carrying out the dyeing in the presence of a soluble salt of an acid alkyl ester having the formula (RO)x-A(OH)n-x'ill which R repreprises carrying out the dyeing in the presence of an alkali metal saltofan acid alkyl ester having the formula (RO)x--A(OH) 11-; in which R represents an aliphatic hydrocarbon radical which contains not more than 5 carbon atoms, A represents the radical S02 or the radical PO, n represents the number of replaceable hydrogen atoms in the uncombined polybasic acid from which'the ester is derivable, and .1: represents a whole number not greater than 1.

5. In the dyeing of textile fibers of the vegetable type by forming an alkaline solution' of a leuco-compound of a vat dye and treating the fiber with said solution, the improvement which comprises carrying out the dyeing in the presence of an organic amine salt of an acid alkyl ester having the formula (RO)x-A-(OH)n-x in which R represents an aliphatic hydrocarbon radical which contains not more than 5 carbon atoms, A represents the radical $02 or the radirepresents a whole number not greater than 1.

6. In the dyeing of textile fibers by forming a improvement which comprises incorporating anv alkali metal salt of an acid alkyl sulfate containing not more than '5 carbon atoms in the alkyl group into a dye bath containing a non-acid solution of a leuco-compound of a vat dye, and working the fiber in the resulting bath.

7. In the dyeing of textile fibers of the vegetable type by treatment with a vat dye, the improvement which comprises incorporating an alkali metal salt of an acid alkyl sulfate containing 3 to 5 carbon atoms in the alkyl group into a dye bath containing an alkaline solutionv of a vat dye in the reduced form, and working the fiber in the resulting bath.

8. In the dyeing of textile fibers of the vegetable type' by treatment with a vat dye, the improvement which comprises incorporating isobutyl sodium sulfate into a dye bath containing an alkaline solution of a vat dye in the reduced form, and working the fiber in the resulting bath.

9. In the dyeing of textile fibers of the vegetable type by treatment with an alkaline solution of a leuco compound of a vat dye, the improvement which comprises treating the fiber to be dyed with a solution of a salt of an acid alkyl ester containing not more than 5. carbon atoms in the alkyl group and derivable from a polybasic inorganic acid and an aliphatic alcohol containing not more than 5 carbon atoms, and subjecting the treated fiber to the dyeing process.

JEAN G. KERN. 

